This invention relates generally to the field of machines used to shave blocks of ice to create small ice particles or shavings for use in drinks or the like. More particularly, the invention relates to such machines which include a means to rotate a block of ice against a shaving plate or blade and a means to press the ice against the blade in the direction of the rotational axis. Even more particularly, the invention relates to such machines where the ice block is axially moved by pneumatic means so that constant pressure is exerted against the ice block during the rotational movement.
There are known ice shaving machines which shave or cut small pieces of ice from a large block of ice so that the shaved ice pieces can be used in drinks or the like. The machines must provide means to move the ice block to the shaving blade as the surface of the ice block is shaved off as well as means to rotate the ice block against the blade to cut the shavings. Typically these two steps are accomplished by providing a mechanical screw drive apparatus where the ice block is temporarily attached to a spiked holder connected to the screw drive. A motor turns the screw which simultaneously rotates the ice block against the cutting blade while advancing the block toward the blade along the rotational axis. These machines produce very poor quality ice shavings with much variation in the size and configuration of the shavings. This is because it is difficult to calibrate the screw drive relative to the shaving action such that axial movement occurs at a steady rate. In other words, the pressure exerted on the ice block, which determines the quality of the shavings, varies greatly during the shaving operation. In addition, because of the mechanical nature of the machines, they are relatively expensive to manufacture and are subject to excessive rates of failure because of the variable stresses exerted on the screw drive mechanism.
It is an object of this invention to provide an ice shaving apparatus which delivers constant pressure against the ice block and shaving blade, such that the quality of the shavings is maximized. It is a further object to provide such an apparatus which is relatively simple to manufacture, is less subject to failure and is easy to operate. These and other objects are realized by providing an ice shaving apparatus where the axial force is supplied pneumatically by pumping air against a piston, where the shaft of the piston is rotated by a separate motor and pulley combination, with the free end of the shaft having a spiked drive plate to grip the ice block.